Map Data Compression Control for Memory Read Caching

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Solution Overview

Problem

Existing memory systems face challenges in efficiently caching map data due to the trade-off between compression ratio and parsing time, which affects read performance and hit rate, particularly in varying memory capacities.

Innovation Solution

A memory system that dynamically adjusts the compression ratio of map data based on available memory capacity, using a compressor to optimize the caching and parsing of map data, thereby managing overhead while maintaining a high hit rate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If map data is compressed at a high compression ratio to increase cache capacity, then the memory capacity utilization is improved, but the parsing time increases and read performance deteriorates

Engineering Contradiction:
Improvecache capacityVSAvoidparsing time
Core Design Contradiction:
Quantity of substanceVSLoss of time

Solution Approach 1:

The patent applies dynamics by making the compression ratio adjustable rather than fixed. The controller dynamically selects different compression ratios based on the available memory capacity, allowing the system to adapt between cache capacity and parsing time requirements. When memory capacity is sufficient, a lower compression ratio is used to reduce parsing time; when memory capacity is limited, a higher compression ratio is used to maximize cache capacity utilization.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of compression ratio based on memory capacity conditions. By varying this parameter, the system optimizes the balance between storing more map data in cache (higher compression ratio) and maintaining fast parsing performance (lower compression ratio). The controller monitors memory capacity and adjusts the compression ratio parameter accordingly to resolve the contradiction.

Inventive Principle:
Principle #35Parameter changes

2Speed

If map data is compressed at a low compression ratio to reduce parsing time, then the read performance is improved, but the cache capacity is reduced and hit rate decreases

Engineering Contradiction:
Improveread performanceVSAvoidcache capacity
Core Design Contradiction:
SpeedVSQuantity of substance

Solution Approach 1:

The system dynamically adjusts the compression ratio based on real-time memory capacity conditions. When memory capacity is sufficient, the system uses a lower compression ratio to prioritize fast parsing and read performance. When memory capacity is constrained, it switches to a higher compression ratio to maximize the amount of map data that can be cached, thereby maintaining hit rate.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The compression ratio parameter is changed according to memory capacity availability. The controller monitors the memory state and selects appropriate compression ratios from a set of predefined ratios, enabling the system to optimize between read performance (faster parsing with lower compression) and cache capacity (more data stored with higher compression).

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the memory capacity is increased to store more map data, then the cache hit rate is improved, but the system cost and complexity increase

Engineering Contradiction:
Improvehit rateVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Instead of increasing memory hardware capacity, the system changes the software parameter of compression ratio to optimize cache utilization. By using higher compression ratios when memory capacity is limited, the system can store more map data entries in the same physical memory space, thereby improving hit rate without adding hardware complexity.

Inventive Principle:
Principle #35Parameter changes

4Quantity of substance

If the compression ratio is increased to maximize cache utilization, then the cache capacity is improved, but the overhead for compression and parsing increases

Engineering Contradiction:
Improvecache capacityVSAvoidcompression overhead
Core Design Contradiction:
Quantity of substanceVSUse of energy by moving object

Solution Approach 1:

The system adjusts the compression ratio parameter based on memory capacity conditions rather than using a consistently high compression ratio. This allows the system to achieve good cache capacity utilization only when necessary (when memory is constrained), reducing the overall compression and parsing overhead while still maximizing cache effectiveness when needed.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS11341040B2Memory system and operating method thereof
Publication Date: 2022.05.24 SK HYNIX INC
  • US11341040B2 patent drawing
  • US11341040B2 patent drawing
  • US11341040B2 patent drawing

AI summary

An operating method of a memory system may include: searching for, in a memory, target map data corresponding to the read request; loading the target map data from a memory device when the target map data are not searched; compressing the loaded target map data using a predetermined compression ratio depending on an available capacity of the memory; caching the compressed target map data in the memory; parsing the compressed target map data; reading target user data corresponding to the read request from the memory device based on the parsed target map data; and outputting the read target user data.